/**
 * @file 移动端rem 布局
 */

(function flexible (window, document) {
  const docEl = document.documentElement
  const dpr = window.devicePixelRatio || 1
  // set 1rem = viewWidth / 23.43
  function setRemUnit () {
    const rem = Math.floor(docEl.clientWidth / 23.43)
    docEl.style.fontSize = `${rem}px`
  }

  setRemUnit()

  // reset rem unit on page resize
  window.addEventListener('resize', setRemUnit)
  window.addEventListener('pageshow', (e) => {
    if (e.persisted) {
      setRemUnit()
    }
  })

  // detect 0.5px supports
  if (dpr >= 2) {
    const fakeBody = document.createElement('body')
    const testElement = document.createElement('div')
    testElement.style.border = '.5px solid transparent'
    fakeBody.appendChild(testElement)
    docEl.appendChild(fakeBody)
    if (testElement.offsetHeight === 1) {
      docEl.classList.add('hairlines')
    }
    docEl.removeChild(fakeBody)
  }
}(window, document))
